I got a case of the new style as well and found a really quick fix. I had some thin plexiglass laying around (stuff you can get at Home Depot), and just cut a rectangle to fit over the area where the express would be mounted. Drilled it to match the standoffs at the outside edges, screwed it in, then just pre-drilled holes for the express and used sheet metal screws to attach it to the plexi. This actually allowed me to mount the express higher up in the case that the originals and gave me some extra working room for the cords. I use the little rubber faucet washers for standoffs too; it keeps board up off the plexi, but it really doesn't matter since it's non-conductive.
Mike E.